Method For Guiding Contact Strips on Solar Modules and a Solar Module

ABSTRACT

The invention relates to a method for guiding contact strips on solar modules which comprise a laminate of a glass plate facing towards the light and a glass plate facing away from the light, and a laminated solar module produced by the method, the photovoltaically active layer of which between the glass plates is connected to contact strips in an electrically conducting manner. It is proposed that the contact strips are led out from the upper side of the glass plate facing away from the light around the edges of this glass plate, are covered with a laminating medium to the underside of this glass plate and with an insulating film to at least over the upper edge of this glass plate and are held in this position for laminating the two glass plates. In the case of a corresponding solar module, the contact strips ( 5 ) are led from the upper side of the glass plate ( 2 ) that is facing away from the light around the edges of this glass plate ( 2 ) and covered with a laminating medium ( 3 ) to the underside of this glass plate ( 2 ) and with an insulating film ( 4 ) to at least over the upper edge of this glass plate ( 2 ).

The invention relates to a method for arranging contact bands in solar modules comprising a laminate of a pane of glass facing the light and a pane of glass facing away from the light as well as a laminated solar module produced by this method, its photovoltaically active layer between the panes of glass being connected to contact strips in an electrically conducting manner.

Contact strips, which collect the current generated in solar modules, must be carried on the (back) side of the module facing away from the light and fed into a contact box.

The solar modules are designed as glass-glass laminates, wherein the photovoltaically active materials may be either thin-film semiconductors or silicon wafers. In either case, the photovoltaically generated current is carried by contact strips from the illuminated side of the module to the side facing away from the light, where they are connected to external contacts in a contact box.

The following boundary conditions must be taken into account in arrangement of the contact strips outside of the laminated module area:

-   -   The contact strips must be protected from corrosion and other         long-term environmental influences.     -   The contact strips must have a high-voltage-proof seal to         prevent input of electric voltage from the outside (e.g., via a         frame).

It is already known that a module may be manufactured with holes in the pane of glass facing away from the light, so the contact strips are fed through these holes, connected to the contact box and then sealed (DE 102 25 140 A1). One disadvantage of this method is the great technological complexity for the subsequent drilling of through-holes and for producing the conducting connections.

It is a different type of production to use a pane of glass on the side facing away from the light such that the pane of glass has smaller dimensions than the opposing piece on the side facing the light. The smaller pane of glass is then laminated centrally onto the larger pane, with the entire back side up to the outer edges of the larger pane of glass additionally being sealed with a suitable insulating material, e.g., Tedlar. In this case, the contact strips are fed between the bottom side of the lower pane of glass and the insulating material up to the position of the contact box, where they are wrapped onto the outside of the module through a slot cut in the insulating material, and then connected to the contact box (“CIS Thin-Film Manufacturing at Shell Solar Practical Techniques in Volume Manufacturing,” Wieting et al., Proceedings of the 31^(st) IEEE PV-Specialists Conference, Orlando, Fla., 2005).

According to another method, in addition to the panes of glass, a suitable electric circuit board is also integrated into the laminate structure, so that the contact strips can be attached to it in the interior of the laminate. The circuit board has appropriate through-contacts, which allow the contact box to be attached to and contacted to the outside (loc. cit.).

A disadvantage of the two methods mentioned last is again the great technological complexity which occurs either due to the need for panes of glass of different sizes and the entire sealing of the back side or due to the additional circuit board and its incorporation into the entire laminate.

The object of the present invention is to provide a technologically simple method for arranging the contact strips and a corresponding solar module.

According to this invention, this object is achieved by the features of claims 1 and 5. Expedient embodiments are the subject matter of the subclaims.

Accordingly,

-   -   the contact strips are wrapped from the top side of the pane of         the glass facing away from the light and around the edges of         this pane of glass,     -   and covered as far as the bottom side of this pane of glass with         a lamination medium and covered with an insulation film up to at         least beyond the upper edge of this pane of glass,     -   and held in this position to laminate the two panes of glass.

A solar module manufactured by this method then has an edge area, where the contact strips are wrapped from the top side of the pane of glass facing away from the light around the edges of this pane of glass and are covered with a lamination medium up to the bottom side of this pane of glass and covered in insulating film up to at least above the upper edge of this pane of glass.

The present invention is based on the fact that the contact strips are fed between the two panes of glass on one side of the module. Up to the edge of the glass, the contact strips are surrounded by lamination medium, e.g., EVA. At the edge of the glass, the contract strips are bent over and fed onto the back side of the pane of glass facing away from the light. For the processing operation, the contract strips can be secured there temporarily to simplify further processing.

To protect the contact strips from environmental influences and high voltage, a fitting piece of insulation film and a piece of lamination medium are placed over the contact strip and likewise secured temporarily to secure the structure to prevent slippage before the actual lamination operation. The entire structure is then subjected to a lamination process of the type conventional in the industry to permanently bond the two panes of glass to one another. By applying the lamination medium between the insulation film and the glass, the contact strips are permanently secured in their positions and the temporary securing means can then be removed.

After lamination, the contact strips can be connected to the contact box.

The contact strips on the bottom side of the pane of glass facing away from the light are either fed through a cut in the insulation film to the outside of the film and into the contact box and then secured on the insulation film or so they overlap on the pane of glass and the insulation film or the contact strips protrude at the end of the insulation film or are fed into the contact box and secured directly to the pane of glass or so they overlap on the pane of glass and the insulation film.

The insulation film may be secured to the side of the module facing away from the light in different ways:

-   -   A first possibility is to wrap the film from the bottom side         vertically over the edges of the two panes of glass, up to the         top side of the pane of glass facing the light and to use         lamination medium over the entire distance and to secure the         film in this way.     -   A second possibility is to wrap the film from the bottom side         vertically over the edge of the lower pane of glass to the top         side of the lower pane of glass and to bond the film and the         contact strips to the bottom side of the pane of glass facing         the light with the help of the lamination medium and thereby         secure them in this way.     -   A third possibility is to wrap the film from the bottom side up         to the upper edge of the pane of glass facing the light and to         secure it with the help of the lamination medium on the glass         edges of the upper and lower panes of glass.

In all cases the film is applied in such a way that the contact strips run between the film and the panes of glass.

The at least two contact strips for carrying current feeds into and away from the contact box may also be arranged in various ways:

-   -   A first possibility is to arrange the contact strips on the top         side of the pane of glass facing away from the light at a joint         location, e.g., in the middle of the shorter side of the panes         of glass, whereby the two contact strips run in parallel without         coming in contact with one another and are arranged between the         two panes of glass and are curved around the pane of glass         facing away from the light to the back side.     -   A second possibility is to have the contact strips emerge         separately at different locations from between the panes of         glass, to bend them onto the back side and continue them onto         the back side of the module and into the contact box, where they         are concealed and protected by the insulation film.     -   A third possibility is to have the contact strips emerge at         different locations between the panes of glass, to arrange them         on the back side and then feed them into separate contact boxes         on the back side of the module, where they are concealed and         protected by the insulation film.

The present invention will be explained in greater detail below on the basis of two exemplary embodiments. In the respective drawings,

FIG. 1 shows schematically a first variant of the inventive contact arrangement and

FIG. 2 shows schematically another variant.

FIG. 1 shows the edge area of a solar module having a photoelectrically active substrate pane of glass 2 and a covering pane 1. From the top side of the substrate pane of glass 2, the current generated is carried over contact strips 5, which are conductingly bonded at the ends to the contact strips on the photoelectrically active coating on the substrate pane of glass 2, onto the back side of the substrate pane of glass 2 to a contact box (not shown here).

The contact strips 5 are wrapped around the edges of the substrate pane of glass 2 and secured there temporarily. Next, a lamination medium 3, e.g., an EVA film, is applied to the substrate pane of glass 2 in such a way that it protrudes beyond the edge of the glass. After applying the cover pane 1, this protruding lamination medium 3 is wrapped around the edges of the cover pane 1 as well as the edges of the substrate pane of glass 2 and covered in the area of the contact strips 5 with an insulation film 4, which, like the lamination medium 3, is wrapped up to the top side of the cover pane 1 in the case shown here. The lamination medium 3 and the insulation film 4 are again secured temporarily. The insulation film 4 and the lamination medium 3 come to an end on the bottom side of the substrate pane of glass 2 before the end of the contact strips 5, so that they protrude and can later be fed into a contact box there.

The solar module is then subjected to a heat treatment in a vacuum in the usual way, during which treatment all the elements are fixedly laminated together. After lamination, the glass-glass laminate is clamped in a profile frame.

FIG. 2 shows a variant with respect to the arrangement of the insulation film 4, which in this case was not wrapped around the pane of glass 1 but instead was wrapped around the edges of the substrate pane of glass 2 as far as the top side before the substrate pane of glass 2 was covered with the cover pane 1. 

1. A method for arranging contact strips in solar modules, comprising a laminate of a pane of glass facing the light and a pane of glass facing away from the light, characterized in that the contact strips are wrapped around the edges of the pane of glass from the top side of the pane of glass facing away from the light, are covered with a lamination medium as far as the bottom side of this pane of glass and are covered with an insulation film up to at least beyond the upper edge of this pane of glass, and are held in this position for lamination of the two panes of glass.
 2. The method according to claim 1, wherein the insulation film is wrapped up to the top side of the pane of glass facing the light.
 3. The method according to claim 1, wherein the insulation film is wrapped up to the top side of the pane of glass facing away from the light.
 4. The method according to claim 1, wherein the insulation film is wrapped up to the upper edge of the pane of glass facing the light.
 5. A solar module comprising a laminate of a pane of glass facing the light and a pane of glass facing away from the light, its photovoltaically active layer being bonded in an electrically conducting manner to contact strips between the panes of glass, characterized in that the contact strips are wrapped from the top side of the pane of glass facing away from the light around the edges of this pane of glass and are covered with a lamination medium as far as the bottom side of this pane of glass and are covered with an insulation film up to at least beyond the upper edge of this pane of glass.
 6. The solar module according to claim 5, wherein the insulation film is wrapped as far as the top side of the pane of glass facing the light.
 7. The solar module according to claim 5, wherein the insulation film is wrapped to the top side of the pane of glass facing away from the light.
 8. The solar module according to claim 5, wherein the insulation film is wrapped up to the upper edge of the pane of glass facing the light. 